The Weather and Climate of West Virginia
Total Page:16
File Type:pdf, Size:1020Kb
ISTOCKPHOTO/CARROLLMT West Virginia by Dr. Kevin T. Law and H. Michael Mogil The Tibbet Knob overlook in George Washington National Forest. est Virginia is a geographically moves a direct Atlantic Ocean influence from its small state that only covers about weather and climate and ensures that the state’s 24,000 square miles. However, climate is more continental than maritime. The due to two distinct two pan- Allegheny Mountains run north to south along Whandles that protrude to the north and east, the the Virginia border and are largely responsible for state’s dimensions are actually 200 miles square. the state’s east-to-west climatological changes. The northern tip extends farther north than The highest point in the state, Spruce Knob, Pittsburgh, Pennsylvania, while the eastern tip has an elevation of 4,863 feet above sea level. is only 60 miles from Washington, D.C. In ad- In fact, the mean elevation in the state is about dition, the southernmost point is farther south 1,500 feet, which is the highest for any state east than Richmond, Virginia, while the westernmost of the Mississippi River. This is more than 500 point is farther west than Port Huron, Michigan. feet higher than Pennsylvania, the second high- The unusual shape and location of the state has est mean elevation for a state. The topography coined the phrase, “West Virginia is the most varies greatly by county, with some individual southern of the northern states, the most north- counties exhibiting elevation changes of more ern of the southern states, and the most western than 3,000 feet. of the eastern states.” West Virginia’s dramatic topographic transi- Temperature tions result in a unique and highly variable cli- Temperatures statewide average about 52°F and mate and weather regime, especially when one naturally increase southward. In the mountains, crosses the state perpendicular to the Allegheny however, elevation changes lead to decreases of Mountains. West Virginia’s inland location re- approximately 5 to 10°F, keeping the annual av- WWW.WEATHERWISE.ORG ■ WEATHERWISE 13 WEST VIRGINIA TECHNICALWEST GIS CENTER Precipitation The average annual precipitation of West Virginia is about 44 inches. However, the pat- tern of the precipitation is strongly influenced by the physical geography, namely, the Allegheny Mountains. Beginning at westernmost points near Huntington and along the Ohio River, where the elevation is approximately 500 feet, precipitation values average near 40 inches per year. Traveling eastward into areas consisting of rolling hills and valleys, the elevation gradually USDA AND NRCS NATIONAL WATER AND CLIMATE CENTER AND CLIMATE WATER ANDUSDA NRCS NATIONAL increases to 750 to 2,000 feet above sea level. This area, which is located in the Ohio River watershed, experiences annual precipitation up to 50 inches, with a major contribution linked to orographic uplift. The elevation dramati- cally increases eastward, reaching altitudes of The average yearly precipitation in West Virginia from 1961–1990. up to 3,500 feet across the Allegheny Plateau. It is in this rugged ridge-and-valley region that erage locked into the 40s. During the winter, the the highest annual precipitation values are re- average daily temperature is about 32°F, while in corded. Pickens (in Randolph County) receives the summer it is about 70°F. Regardless of sea- more than 64 inches a year on average. The ridge son, the daily temperature range runs between 20 of the Alleghenies (with peak elevations of just and 25°F. The record high temperature of 112°F over 4,800 feet) lies just east of the plateau. The occurred in Martinsburg in 1936, and the record ridge line divides the Ohio River watershed from low temperature of –37°F occurred in Lewisburg the Potomac/Chesapeake Bay watershed, which in 1917. The record high occurred in one of the drains the eastern third of the state. Precipitation warmest years on record; in fact, 15 other states decreases substantially east of the ridge due to have their record annual high temperature shar- the orographic rain-shadow effect. As the eleva- ing the same year. tion rapidly decreases, so too does precipitation. 14 WEATHERWISE ■ MARCH / APRIL 2011 Here, the South Branch (of the Potomac) Valley, Clouds and Fog with less than 36 inches of precipitation, is the West Virginia is also one of the more cloudy driest area in the state. The eastern panhandle areas of the country. Beckley, Elkins, and also consists of steep slopes and valleys oriented Huntington all average about 200 days per southwest to northeast. Again, elevation in this year with overcast conditions. These locations rain shadow region decreases rapidly, reaching are among the cloudiest in the eastern United approximately 240 feet, the lowest in the state. States. Fog is predominantly responsible, and Similarly, rainfall drops off, as well. Only about it is prevalent throughout the state due to two 40 inches of precipitation falls near Harper’s primary factors. The first factor is linked to high Ferry along the Potomac. evapotranspiration rates from extensive forest Annual snowfall totals show a similar geo- cover. The second factor is rapid nighttime radia- graphic pattern, with lower values in the south- tion loss from elevated locations and the ensu- western lowlands near Huntington and “snow- ing cold air drainage that often fills valleys. This shadow” regions in the eastern part of the state. combination causes West Virginia to be one of Higher values are also focused in the northern the foggiest locations in the country, with several mountains. The annual snowfall ranges from 12 towns reporting dense fog (visibilities below 0.25 to 24 inches in those southwestern lowlands, miles) for at least 40 days per year. while it is greater than 72 inches in the moun- tains. West Virginia is the southernmost state in Major Weather Events the east that experiences snowfall amounts this West Virginia has a wide array of severe great. Snowfall amounts in the Alleghenies rival weather including thunderstorms and snow- those found in favorable lake-effect areas in New storms. Tornadoes are rare (only an average of York and Pennsylvania. two per year), primarily because of the climate NATIONAL PARK SERVICE PARK NATIONAL West Virginia is one of the foggiest locations in the country. Here, fog swirls around the base of the New River Gorge Bridge. WWW.WEATHERWISE.ORG ■ WEATHERWISE 15 THE MOOREFIELD EXAMINER In 1985 the remnants of Hurricane Juan produced flash floods across the state. Here, Main Street in Moorefield, West Virginia, stands under several feet of water. created by the state’s unique topography. The few that do occur are usually minor in intensity. However, during the famous April 3-4, 1974, na- tionwide tornado outbreak there were at least six tornadoes reported in the state. On April 9, 1991, a derecho event developed from a bow echo that THE MOOREFIELD EXAMINER raced across the state. Winds exceeded 80 mph in many parts of the state, with more than 200,000 residents losing electricity. Two deaths and 86 in- juries were also attributed to these high winds. Not since the 1974 tornado super-outbreak had there been so much damage. However, flooding is by far the deadliest and costliest weather-related disaster in the state. Every year, heavy rainfall over the steep, rugged topography creates flood or flash flood events. The two most memorable flood events occurred in 1937 and 1985. 1937 Great Ohio River Flood The 1937 flood remains on the record books for the southwestern part of the state near The 1985 flooding wreaked havoc across Moorefield, West Virginia, including the Heck’s Huntington. This flood affected all parts of the General Store. 16 WEATHERWISE ■ MARCH / APRIL 2011 Ohio River from Pennsylvania to Illinois but hit was shut off in the city for more than a week, and especially hard in southwestern West Virginia. natural gas was not available for 40 percent of The river at Huntington crested at 69 feet (19 the residents for two weeks. Five residents died feet above flood stage), a record that still stands and there was more than $18 million (in 1937 today. Heavy rainfall occurred over a two-week dollars) in damages linked to the event. After period from January 13 to 25 that year, with the Great Ohio River Flood, 39 flood-control amounts ranging from 6 to 12 inches in the re- dams were built upstream to prevent such a cata- gion. This was four times the average January strophic flood from occurring again. precipitation and amounted to almost 20 percent of the average annual total. The persistent warm 1985 Flash Flooding January rainfall on already saturated ground It is not uncommon for West Virginia to re- (from December snow-cover melt) coupled with ceive heavy rainfall from tropical cyclones mak- the drainage from neighboring regions created ing landfall (e.g., Hurricane Camille, 1969; unprecedented flooding. Local newspapers re- Hurricane Ivan, 2004), but in 1985 the rem- ported that small buildings were floating down nants of Hurricane Juan produced flooding that the streets and that homes were pushed off of residents will never forget. Hurricane Juan made their foundations. Many homes and buildings landfall in Louisiana as a Category 1 storm and were without power and heat because of blown gradually moved toward the northeast. As Juan fuses and electrical wiring faults. Restaurants ran weakened and became extratropical, it interacted out of food and it was estimated that 6,000 peo- with an upper-level low-pressure system that was ple in the city were left homeless. Drinking water “cut off” from the main flow. As Juan’s remnants NOAA The surface and upper air weather maps for November 26, 1950, shows the The Great Appalachian Storm of November 1950, which dropped as much as 57 inches of snow on parts of the state.